Fructose Malabsorption

When we eat fruit, fructose (the sugar found in fruit) passes through the walls of the small intestine lining into the blood stream. Once in the blood it is converted into glucose which the body utilises to burn for energy (like a fuel of a motor). For the fructose to pass through the small intestine lining there is a mechanism (called transport mechanism) and if this is defective fructose remains in the gastro intestinal tract causing Carbohydrate Intolerance symptoms as those associated with other food intolerance, such as lactose. Fructose Malabsorption must not be confused with Fructose Intolerance, the condition which lacks the enzyme to convert fructose into glucose.


This condition is common in patients with symptoms of lactose intolerance and irritable bowel syndrome. A small proportion of patients with both fructose mal absorption and lactose intolerance also suffer from coeliac (celiac) disease. Typical symptoms of fructose mal absorption include:

Symptoms list:

  • bloating
  • diarrhoea and / or constipation
  • flatulence
  • stomach pain (due to muscle spasms, which can vary from mild and chronic to acute but erratic)

Other possible symptoms of fructose mal absorption include:

  • aching eyes
  • fuzzy head
  • fatigue
  • depression

Fructose in Foods

Symptoms list:

  • aching eyes
  • fuzzy head
  • fatigue
  • depression

Fructose in Foods

Foods with a high fructose content include:

  • apples
  • coconut milk
  • fruit juice (especially from apples and pears)
  • guavas
  • high fructose corn syrup (present in some soft drinks, and used to make sushi rice stick together)
  • honey
  • lychees
  • mangos
  • melons
  • pawpaw
  • pears
  • persimmons
  • quince

Other foods with fructose

In addition, the following foods can cause symptoms of fructose mal absorption:

  • dried fruit (including "health" bars containing dried fruit)
  • tinned fruit in "natural" juice (which is often pear juice)
  • sorbitol (present in some diet drinks and foods, and occurring naturally in some stone fruits)
  • sweet wines
  • Too much fruit of any kind in a short time frame


There is no cure for Fructose mal absorption and it is very difficult for undiagnosed sufferers to see any relationship between the foods they eat and the symptoms they suffer, even if they keep a daily diet diary. This is because most foods contain a mixture of fructose and glucose. Foods with more fructose than glucose are a problem, as are foods with a lot of fructose (regardless of the amount of glucose). The only way of treating it is by limiting the diet to lower levels of fructose. The amounts one can consume asymptomatically varies from one person to another. When this is found out one can stick to that level of fructose in the diet and avoid the symptoms.

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